1. Field of the Invention
The present invention relates to a method for manufacturing a heat sink. More particularly, the present invention relates to a method for manufacturing a heat pipe and a capillary structure thereon.
2. Description of Related Art
With the development of science and technology, electronics have become indispensable in people's daily life. As for a certain electronic product, it can only operate normally and maintain a proper life span under an appropriate temperature. However, as the electronic components inside the electronic product continuously generate heats, these components that generate high heats can only maintain a stable operating temperature through a favorable heat dissipation manner, for example, dissipating heats through a heat sink. Taking an information device for example, in order to improve the heat dissipation efficiency and avoid the noises caused by a fan, a heat pipe has been used to dissipate heats in the mainframe of a computer.
The working principle of the heat pipe is to transfer heats through evaporation and condensation of a fluid. First, a proper working fluid is poured into the heat pipe at a negative pressure state, and the heat pipe has a capillary structure made of a porous material formed on the wall. Next, the working fluid is evaporated at an evaporator, to absorb the heat emitted by components around the evaporator. Then, under a minor pressure difference, the vapor flows towards a condenser to be condensed and to emit heats. Finally, the working fluid condensed at the condenser flows back to the evaporator through the capillary structure under the capillarity effect. Therefore, the working fluid is continuously evaporated and condensed as a circle, so as to dissipate the heats generated by the components around the evaporator.
As the capillary structure in the heat pipe plays an important role in transferring the working fluid, the design of the capillary structure is extremely important, in which the shape, volume, and thickness may possibly affect the heat dissipation efficiency.
FIG. 1 is a schematic view of a conventional heat pipe. Referring to FIG. 1, the heat pipe 100 includes a copper pipe wall 110 and a capillary structure 120. During the manufacturing of the conventional heat pipe 100, a central cylindrical rod is generally employed as a mold to form the capillary structure 120 in the heat pipe 100. Thus, the surface of the conventional capillary structure 120 is usually a plane or of a simple configuration, which relatively restricts the structural design and heat dissipation efficiency of the heat pipe. In particular, theoretically, the thinner the capillary structure 120 is, the better the circular effect of the working fluid in the heat pipe 100 will be, and thus achieving a preferred heat dissipation efficiency. However, in practice, the working fluid that can be absorbed by the capillary structure 120 is getting increasingly less as the capillary structure 120 becomes thinner, which thus restricts the total heats taken by the working fluid. On the other aspect, after considering the normal operation of the process and capillarity, etc., it is found that the thickness of the capillary structure 120 cannot be unrestrictedly reduced. Therefore, the currently available capillary structure 120 formed through a central cylindrical rod cannot achieve an optimal design, and also affects the heat dissipation performance of the heat pipe 100.